content: /**
   * Copyright (c) 2016-present, RxJava Contributors.
   *
   * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in
   * compliance with the License. You may obtain a copy of the License at
   *
   * http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software distributed under the License is
   * distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See
   * the License for the specific language governing permissions and limitations under the License.
   */
  
  package io.reactivex.observable.internal.operators;
  
  import java.util.Collection;
  import java.util.concurrent.Callable;
  import java.util.concurrent.atomic.AtomicReference;
  
  import io.reactivex.common.*;
  import io.reactivex.common.exceptions.Exceptions;
  import io.reactivex.common.internal.disposables.DisposableHelper;
  import io.reactivex.common.internal.functions.ObjectHelper;
  import io.reactivex.observable.*;
  import io.reactivex.observable.internal.disposables.EmptyDisposable;
  import io.reactivex.observable.internal.observers.QueueDrainObserver;
  import io.reactivex.observable.internal.queues.MpscLinkedQueue;
  import io.reactivex.observable.internal.utils.QueueDrainHelper;
  import io.reactivex.observable.observers.*;
  
  public final class ObservableBufferBoundarySupplier<T, U extends Collection<? super T>, B>
  extends AbstractObservableWithUpstream<T, U> {
      final Callable<? extends ObservableSource<B>> boundarySupplier;
      final Callable<U> bufferSupplier;
  
      public ObservableBufferBoundarySupplier(ObservableSource<T> source, Callable<? extends ObservableSource<B>> boundarySupplier, Callable<U> bufferSupplier) {
          super(source);
          this.boundarySupplier = boundarySupplier;
          this.bufferSupplier = bufferSupplier;
      }
  
      @Override
      protected void subscribeActual(Observer<? super U> t) {
          source.subscribe(new BufferBoundarySupplierObserver<T, U, B>(new SerializedObserver<U>(t), bufferSupplier, boundarySupplier));
      }
  
      static final class BufferBoundarySupplierObserver<T, U extends Collection<? super T>, B>
      extends QueueDrainObserver<T, U, U> implements Observer<T>, Disposable {
  
          final Callable<U> bufferSupplier;
          final Callable<? extends ObservableSource<B>> boundarySupplier;
  
          Disposable s;
  
          final AtomicReference<Disposable> other = new AtomicReference<Disposable>();
  
          U buffer;
  
          BufferBoundarySupplierObserver(Observer<? super U> actual, Callable<U> bufferSupplier,
                                                  Callable<? extends ObservableSource<B>> boundarySupplier) {
              super(actual, new MpscLinkedQueue<U>());
              this.bufferSupplier = bufferSupplier;
              this.boundarySupplier = boundarySupplier;
          }
  
          @Override
          public void onSubscribe(Disposable s) {
              if (DisposableHelper.validate(this.s, s)) {
                  this.s = s;
  
                  Observer<? super U> actual = this.actual;
  
                  U b;
  
                  try {
                      b = ObjectHelper.requireNonNull(bufferSupplier.call(), "The buffer supplied is null");
                  } catch (Throwable e) {
                      Exceptions.throwIfFatal(e);
                      cancelled = true;
                      s.dispose();
                      EmptyDisposable.error(e, actual);
                      return;
                  }
  
                  buffer = b;
  
                  ObservableSource<B> boundary;
  
                  try {
                      boundary = ObjectHelper.requireNonNull(boundarySupplier.call(), "The boundary Observable supplied is null");
                  } catch (Throwable ex) {
                      Exceptions.throwIfFatal(ex);
                      cancelled = true;
                      s.dispose();
                      EmptyDisposable.error(ex, actual);
                      return;
                  }
  
                  BufferBoundaryObserver<T, U, B> bs = new BufferBoundaryObserver<T, U, B>(this);
                  other.set(bs);
  
                  actual.onSubscribe(this);
  
                  if (!cancelled) {
                      boundary.subscribe(bs);
                  }
              }
          }
  
          @Override
          public void onNext(T t) {
              synchronized (this) {
                  U b = buffer;
                  if (b == null) {
                      return;
                  }
                  b.add(t);
              }
          }
  
          @Override
          public void onError(Throwable t) {
              dispose();
              actual.onError(t);
          }
  
          @Override
          public void onComplete() {
              U b;
              synchronized (this) {
                  b = buffer;
                  if (b == null) {
                      return;
                  }
                  buffer = null;
              }
              queue.offer(b);
              done = true;
              if (enter()) {
                  QueueDrainHelper.drainLoop(queue, actual, false, this, this);
              }
          }
  
          @Override
          public void dispose() {
              if (!cancelled) {
                  cancelled = true;
                  s.dispose();
                  disposeOther();
  
                  if (enter()) {
                      queue.clear();
                  }
              }
          }
  
          @Override
          public boolean isDisposed() {
              return cancelled;
          }
  
          void disposeOther() {
              DisposableHelper.dispose(other);
          }
  
          void next() {
  
              U next;
  
              try {
                  next = ObjectHelper.requireNonNull(bufferSupplier.call(), "The buffer supplied is null");
              } catch (Throwable e) {
                  Exceptions.throwIfFatal(e);
                  dispose();
                  actual.onError(e);
                  return;
              }
  
              ObservableSource<B> boundary;
  
              try {
                  boundary = ObjectHelper.requireNonNull(boundarySupplier.call(), "The boundary Observable supplied is null");
              } catch (Throwable ex) {
                  Exceptions.throwIfFatal(ex);
                  cancelled = true;
                  s.dispose();
                  actual.onError(ex);
                  return;
              }
  
              BufferBoundaryObserver<T, U, B> bs = new BufferBoundaryObserver<T, U, B>(this);
  
              Disposable o = other.get();
  
              if (!other.compareAndSet(o, bs)) {
                  return;
              }
  
              U b;
              synchronized (this) {
                  b = buffer;
                  if (b == null) {
                      return;
                  }
                  buffer = next;
              }
  
              boundary.subscribe(bs);
  
              fastPathEmit(b, false, this);
          }
  
          @Override
          public void accept(Observer<? super U> a, U v) {
              actual.onNext(v);
          }
  
      }
  
      static final class BufferBoundaryObserver<T, U extends Collection<? super T>, B>
      extends DisposableObserver<B> {
          final BufferBoundarySupplierObserver<T, U, B> parent;
  
          boolean once;
  
          BufferBoundaryObserver(BufferBoundarySupplierObserver<T, U, B> parent) {
              this.parent = parent;
          }
  
          @Override
          public void onNext(B t) {
              if (once) {
                  return;
              }
              once = true;
              dispose();
              parent.next();
          }
  
          @Override
          public void onError(Throwable t) {
              if (once) {
                  RxJavaCommonPlugins.onError(t);
                  return;
              }
              once = true;
              parent.onError(t);
          }
  
          @Override
          public void onComplete() {
              if (once) {
                  return;
              }
              once = true;
              parent.next();
          }
      }
  }
  